Understanding linux shell script expression -


hi have small script (script name is: test1.sh) looks this

prg=$0 data=`expr $prg : '.*\/.*'` echo $data

when run see output as

10

i not understand regular expression written in second line of script. mean?

the expression returns non-zero value if there / within relative filename of script ($0 in sh). if execute script this: sh ../../script.sh, outputs 15, total length of "../../script.sh". matches "../../" '.*\/ , matches script.sh .* part.


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